distribute	reads
0-500	14286
500-800	27084
800-1000	23685
1000-1200	25865
1200-1400	27447
1400-1600	25514
1600-1800	20185
1800-2000	14454
2000-2200	9735
2200-2400	5805
2400-2600	2870
2600-2800	1302
2800-3000	582
>3000	327
